Reproducer



Nov. 25, 1930.

E. w. KELLOGG 1,783,044

REPRODUCER Filed Dec. 1, 1935 2 Sheets-Sheet l ITiveTfltOY- Edward W. Kellogg His Attorney.

Nov. 25, 1930 E; w. KELLOGG I 1,783,044

REPRODUQER Filed Dec. 1 1925 I 2 Sheets-Sheet 2 Inventor: Edward W. Kel I022,

His Attovney.

spective view .Patented Nov. 25, 1930 EDWARD W. KELLOGG, 0F SCHENEC'IYADY, NEW

YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK REPRODUCER Application filed December My invention relates to devices for producing sound. and has for its principal object the provision of an improved piek-up device that is rugged in construction and is capable of accurately reproducing sound from phonographic records or the like.

Various devices have been utilized in the past to reproduce sound either directly or by the generation of electromagnetic impulses dependent on the character of the sound to be transmitted. Some of. these devices involve the; use of parts that are moved in accordance with the contour of a record, such for example as the groove of a phonographic record. Where the use of moving parts is involved. difficulty is frequently encountered due to sound distortion produced by the tendency of these parts to vibrate at a frequency dependent on their free vibration period; A further diiiiculty involved in the use of pick-up devices comprising a phonographic stylus or needle is the difiiculty of attaching the needle to its holder in a manner to ensure the accurate reproduction of sound. Tr. accordance with my invention these difliculties are minimized or altogether avoided by the provision of a movable member wherein the center of mass coincides with the axis of rotation and by the further provision of a clamping arrangement wherein pressure is applied to the needle in a manner to ensure engagement of the needle with the needle holder at predetermined points of conta t.

My invention will be better understood from the following description when considered in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a perof a sound reproducing device wherein my invention has been embodied; Fig. 2 shows the device with its cover plate removed: Fig. 3 is a sectional view of the device; Fig. 4 shows the device with its interior parts removed: Figs. 5 and. 6 show various details of the device; and Figs. 7 and 8 show a modification in certain of these details.

Y V Fig. 1 shows a disk record 1 which is adapt- 1, 1925- Serial No. 72 541.

interposed between the lower ends of the magnet as indicated in Fig. 2. An armature 11 pivoted between the edges of the lower flanges of the pole pieces 10 is surrounded by a coil 12 interposed between the 7 upper and lower flanges of the pole pieces 10. The coil 12 is adapted to be. connected to an external circuit throughconductors 13 supported by an insulation terminal block 14 which is attached to the upper flanges of the pole pieces 10 by means of screws 15. The cover member 6 is clamped to the member 5 by means of screws 16 threaded into the nonmagnetic member 9. e

As shown more clearly in Figs; 3 and 4, the armature 11 is provided with a shaft 17 mountedin a bearing between the lower pole piece flanges. This bearing comprises journals or sleeves 18 made of rubber or other resilient material by which friction is avoided and the armature is biased to its mid-position. It will be observed that the needle 19 is clamped in the end of the armature 11 by means'of a screw 20 threaded into the end of the armature shaft-along its rotational axis; and that rubber pads 21 are provided at the end of the armature for damping its motion and producing a biasing force augmenting that exerted through the resilient journal 18. As indicated by Figs.-7 and 8 the resilient journal 18 obviously may be replaced by a spring 24 which is held in contact with the armature shaft in any suitable manner.

It has been found that the weight of the reproducer on the needle point tends to bend. the needle out of co'ntact with the lower end of the armature as indicated by Fig. 5, thus producing uncertain contact between the needle and armature. In order to avoid this uncertain clamping, the armature is distorted at its end as shown by Fig. 6 to form lips 22 upon which the needle rests. With this construction, tightening of the set screw 20 applies a pressure at the center of the needle and bends it slightly so that positive cont-act is maintained between the needle and the end tromotive force determined by the contour of the record. It will be apparent that this electromotive force may be applied to any suitable amplifying and reproducing device for reproducing the recorded sounds or may be utilized in other ways.

The embodiment of the invention illus trated and described herein has been selected for the purpose of clearly setting forth the principles involved. It will be apparent however that the invention is susceptible of being modified to meet the different conditions encountered in its use and I therefore aim to cover by the appended claims all modifications within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. The combination ef a magnet, an armature mounted in a resilient bearing and adapted to be rocked to and fro between the poles of said magnet for varying the path of the flux transmitted between said poles, and

means disposed about the rotational axis of said armature for clamping a stylus to said armature.

2. The combination of a magnet, an armature mounted in a bearing and adapted to be moved between the poles of said'magnet for varying the path of the flux transmitted between said poles, and means symmetrically disposed about the axis of said bearing for clamping a stylus to said armature.

3. The combination of a magnet, a stylus, an armature interposed in the flux pat of said magnet and provided with a square s aft mounted in a resilient bearing, and means movable along the axis of said shaft for holding said stylus in said armature.

4. The combination of a magnet, an armae ture for said magnet mounted in a resilient bearing and provided with a plurality of stylus holding surfaces, and means symmetrically disposed about the rotational axis of said armature for producing pressure. at a point intermediate said surfaces.

aveaoaa 5. The combination of an armature member adapted to be rocked to and fro and provided with a plurality of stylus holding surfaces, and clamping means symmetrically disposed about the rotational axis of said armaturefor producing pressure at a point intermediate said surfaces.

6. A stylus holder comprising a shaft, a plurality of stylus holding surfaces, and means movable along the axis of said shaft for applying a clamping pressure at a point intermediate said surfaces.

7. The combination of a magnet, a stylus, a coil interposed in the flux path of said magnet, an armature having a rigid non-circular shaft extending at right an ,les thereto, a resilient bearing for said shaft adapted to maintain said armature in a central position, said armature being adapted to be rocked to and fro for varying the path of the flux trans mitted through said coil by said magnet, and means movable along the axis of said shaft for holding said stylus in said armature.

8. The combination of a magnet, a coil interposed in the flux path of said magnet, an armature having a rigid shaft extending at right angles thereto, a resilient bearing for said shaft, one end of said shaft being adapted to receive a stylus, and means extending through the shaft to hold a stylus in position, said armature being adapted to be rocked to and fro by means of a stylus for varying the path of the flux transmitted through said coil by said magnet.

9. The combination of a magnet, opposite 1 n pole tips for said magnet each having a pair of flanges, each of the flanges of each pole tip bein separated from the corresponding flange o the opposite pole tip by a short air gap, an armature having a shaft journalled in one of said air gaps and having a free end ada ted to vibrate in the other air gap.

10. T e combination of a magnet, opposite pole tips for said magnet each having a pair of flanges, each of the flanges of each pole tip being separated from the corresponding flange of the opposite pole tip by a short air gap, an armature having a rigid shaft and a resilient bearing for said shaft 10* cated in one of said air gaps, said armature having a free end adapted to vibrate in the other air gap.

11. The combination of a magnet, opposite poletips for said magnet, each having a pair of flanges, each of the flanges of each pole tip being separated from the corresponding flange of the opposite pole tip by a short air gap, an armature having a rigid shaft, and a resilient bearing for said shaft in one of said air gaps so arranged as to maintain the armature normally in a central position, said armature having a free end which is adapted to vibrate in-the other air gap.

12. The combination a magnet, opposite pole tips for said nrxgnet, each having tip being separated from being adapted to vibrate I and means extending through said shaft holding a stylus interposed in the flux path an v armature. having a rigid non-circular a pair of flanges, each of theflanges of each ceive a stylus, and means extending through the correspondpole tip being separated from the opposite pole tip by a short ing flange 0 air gap, extending at right angles thereto, and a resilient bearing for said shaft located in one of said air gaps, one end of said armature being adapted to receive a stylus and-the other end of said armature being adapted to vibrate in the other air gap.

13. The coinbination of a magnet, opposite an armaturevhaving a rigid shaft said shaft for my hand this 30th day EDWAR pole tips for said magnet each having a pair of flanges, each of the flanges of each pole the corresponding flange of the opposite pole tip by a short air gap, an armature having a rigid shaft ex tending at right angles thereto, a resilient bearing for said shaft located in one of said air gaps, one end of said armature being adapted to-receive a stylus, the other end in the other air gap, for in position.

14.The combination of a magnet having opposite pole'tips, an armature adapted to rotate about an axis and having a portion,

adapted to vibrate between said pole tips, one end of said armature being adapted to receive a stylus, and holding means for the stylus located in the axis of rotation of the armature.

15. The combination of opposite pole tips, an armature having a shaft extending at right'angles thereto, one end of said armature being adapted to receive a stylus and the other end being adapted to vibrate between said pole tips, and holding means for a stylus extending through said shaft. 16. The combination of a magnet, opposite pole tips for said magnet, an armature having a shaft extending at right angles thereto, a resilient bearing for said shaft, one end of said armature being adaptedto receive a stylus and the'other end being adapted to vibrate between the pole tips, and holding meairfils for said stylus extending through said sha 17. The combination of a magnet, an armathe flux path of said provided with a square shaft oldina' said stylus in position.

18. The combination of a magnet, a coil of said magnet,

shaft extending at right angles thereto, a resilient bearing for .said

a magnet having resilient bearing, one end of said said shaft for shaft adapted tomaintain said armature ina central position, said. armature being adapted to be rocked to and\fro for varying the path of the-flux transmitted'throu'gh said coil by said magnet, one end of said armature'being adapted toreholding said stylus in position. In witness whereof,

I have hereunto set of November, 1925. D W. K'ELLOGG. 

